diff --git a/include/llvm/CodeGen/AsmPrinter.h b/include/llvm/CodeGen/AsmPrinter.h
index 36fb68b..27248de 100644
--- a/include/llvm/CodeGen/AsmPrinter.h
+++ b/include/llvm/CodeGen/AsmPrinter.h
@@ -369,6 +369,10 @@
     /// operands.
     virtual MachineLocation getDebugValueLocation(const MachineInstr *MI) const;
 
+    /// getISAEncoding - Get the value for DW_AT_APPLE_isa. Zero if no isa
+    /// encoding specified.
+    virtual unsigned getISAEncoding() { return 0; }
+
     //===------------------------------------------------------------------===//
     // Dwarf Lowering Routines
     //===------------------------------------------------------------------===//
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 513e6ad..5618f09 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -1336,6 +1336,10 @@
   if (SP.isOptimized())
     addUInt(SPDie, dwarf::DW_AT_APPLE_optimized, dwarf::DW_FORM_flag, 1);
 
+  if (unsigned isa = Asm->getISAEncoding()) {
+    addUInt(SPDie, dwarf::DW_AT_APPLE_isa, dwarf::DW_FORM_flag, isa);
+  }
+
   // DW_TAG_inlined_subroutine may refer to this DIE.
   SPCU->insertDIE(SP, SPDie);
 
diff --git a/lib/Target/ARM/ARMAsmPrinter.cpp b/lib/Target/ARM/ARMAsmPrinter.cpp
index 3cc6c8f..003bdac 100644
--- a/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -56,6 +56,15 @@
 EnableMCInst("enable-arm-mcinst-printer", cl::Hidden,
             cl::desc("enable experimental asmprinter gunk in the arm backend"));
 
+namespace llvm {
+  namespace ARM {
+    enum DW_ISA {
+      DW_ISA_ARM_thumb = 1,
+      DW_ISA_ARM_arm = 2
+    };
+  }
+}
+
 namespace {
   class ARMAsmPrinter : public AsmPrinter {
 
@@ -196,6 +205,14 @@
     void EmitStartOfAsmFile(Module &M);
     void EmitEndOfAsmFile(Module &M);
 
+    virtual unsigned getISAEncoding() {
+      // ARM/Darwin adds ISA to the DWARF info for each function.
+      if (!Subtarget->isTargetDarwin())
+        return 0;
+      return Subtarget->isThumb() ?
+        llvm::ARM::DW_ISA_ARM_thumb : llvm::ARM::DW_ISA_ARM_arm;
+    }
+
     MCSymbol *GetARMSetPICJumpTableLabel2(unsigned uid, unsigned uid2,
                                           const MachineBasicBlock *MBB) const;
     MCSymbol *GetARMJTIPICJumpTableLabel2(unsigned uid, unsigned uid2) const;